Bordetella pertussis exerts a profound and complex influence on immunological responsiveness. However, little information exits concerning the cellular mechanisms involved, especially in regard to influences on macrophage function. This study will define the interaction of pertussis antigens with immune cells mechanisms by examining pertussis influence on macrophage phagocytosis, spreading, chemotaxis, bactericidal activity, and accessory cell activity for in vitro antibody formation. Furthermore, because pertussis is composed of a variety of biologically active substances, the influence on macrophage of pertussis-derived heat-labile toxin (HLT), endotoxin (LPS), pertussigen (HSF), and other factors to be purified will be determined. The proposed project will examine the macrophage as a preferential target of pertussis activity and define the relationship between specific pertussis components and alteration of macrophage function. Pertussis organisms will be cultivated in specifically defined medium and phase I character and potency of the bacterium determined. Varying doses of whole cell preparations will be injected by various routes into mice and functional ability of explanted peritoneal macrophages assessed. Also, the in vitro influence of pertussis on cultured normal and exudate macrophages will be determined. Changes in ability of macrophages to: 1. phagocytize EAC rosettes; 2. rapidly spread on a glass surface; 3. migrate in a unidirectional manner toward a constant stimulus; 4. ingest and kill intracellular bacteria; and 5. support the in vitro anti-SRBC antibody response, will be examined. In addition, pertussis organisms will be extracted and HLT purified by ion exchange chromatography, LPS by repeated differential centrifugation and HSF by gel filtration chromatography. The in vivo and in vitro influence of these pertussis fraction on macrophage function will be determined. These studies will examine in detail the mechanism of action of pertussis vaccine and components on these important parameters of macrophage function.